Haloperidol does not attenuate conditioned place preferences or locomotor activation produced by food- or heroin-predictive discriminative cues

The present study examined whether a discriminative cue previously predictive of food or heroin reinforcement could activate and direct behavior in an environment that had never been paired with primary reinforcement. Olfactory cues, predicting the availability (S+) or unavailability (S-) of either heroin (0.1 mg/kg IV) or food (45 mg Noyes food pellets) reinforcement in the goal box of a straight-arm runway, were later tested in a separate environment for their ability to elicit locomotion (activate behavior) or induce a conditioned place preference (direct behavior). Presentation of the S+, but not the S-, resulted in a reliable increase in spontaneous locomotor activity that was not blocked by pretreatment with the dopamine receptor antagonist, haloperidol. Similarly, subjects displayed a preference for a novel location in which the S+, but not the S-, was placed. This preference was also unaltered by pretreatment with haloperidol. These data suggest that discriminative cues can profoundly affect behavior, even in environments that have themselves never been associated with primary reinforcement. Additionally, the conditioned motivational quality of these cues is unaltered by treatment with the same dopamine receptor antagonist shown in previous work to attenuate the primary reinforcing properties of heroin and food. (C) 1999 Elsevier Science Inc.